Ultra short wave reception



s translationv of modulated Aultra short Wavelength Hausen-Kurz oscillations.l

Patented Aug. 20, 1935 o ULTnArsnoRTWAvE vR'Eciir'rioN- Nils'E.y Lindenblad, Port Jefferson; Y., assignor`r to Radio Corporation of of Delaware America, a corporation connus. (cremig-zo) 'Iill'x'isinvention relates to apparatus for undulatingelectrieal energy and especiallyfto a re-y 1 devices. The production of 'ultra short Waveoscillations under such conditions maybe ascribed't'o tlielfa'ct that 'electrons attracted-towards theconf trolvelectrode or grid'passi through the gridfstruotnre'and', upon approaching a relatively negatively charged anode', `are caused'to return' towards ythe grid, p'artlydue to the attractive action of the positive charge'onjjhel grid'andipartly due, to the repelling. effectrof the' negatively chargedd anode. The returning electronsv again rush through the i grid only to approach the cathode', vvherethecoinbinedsp'ace chargeaswell as theattractinglforce of .the grid causes the electrons to repeatthe cycle outlinedl The oscillationsv so vpro'c'lucedfare of ultra short wave. lengthsl and' are known' as Bark- 11nv order. to modnlatelsuch',voscillations, audio frequency modulation has been directly 'applied to fthe *oscillatory energy so producedif and, Ethe ultrashort,` Wave length n energy. has been moduo lated yby@relativelylow radioA frequency-L oscilla# tionsl modulated at audio frequencies giving what wave length oscillations. y s

`is known as Vdouble modulation ofthe vultraishort dyning andamplification, dexnodulation and energyfv such as described hereinabove. More specically,-it-is anobject of myinvention to pro- Vide the combination', inannltra-Ushortwave receivingesystem", of `an--antenna for collecting @ultra short= Wavelength energy, .a tuning circuit espe.V

cially-A adapted forA resonating` the; collected ultra short yvvaveflength energy,one or more. oscillatore detector; electron dischargedevices forgthehetero- .dyningandamplication of the resonated energy, and means to demodulate and translate the am- 4pliiied-interinadiate1frequency energy.v

Still a further object of the present invention ist@ ,provide for hetefodyning` and 'amplification f purposes, one-or more electron disclflargev devices havingztheir control electrodes or grids maintained the devices; adiustaloly:y coupled towtheI tuning ,cir-

' ingdrawingwhich is given rnerelyloyfway'f l"- cuit for resonating thecollectedenergy,v in'xconrbinatic'nnv Withfpreferably; aI regenerative detecV devices.

y tor'for vdemodul'ating the energyamplifiedibythe "ihm/ foundjthar-by the v'use afar-,uned radio freqllency'fregenerative *circuitY for demodul'atig the ampli-fied: intermediate frequencyy oscillations;

the regenerative.A circuit W'ill givea'pproximately the saine 'amplification{Whetherv'double mo'dula tion is employed at the transmittingend orf'the transmitted oscillations are only'v 'modulated 'difrectly by'l'audiolffrequency energy;`y In' theevnt of donniev modulation, the interifnediate"ire'q'l'iency circuit at'the -receivin'g'end should-of courseQfbe tuned :to "the "intermediate fflfrequ'eney `used ati yche transmitting end of therlsyste'm; If'desii'ed, vinjthe': c'ase ofdoub'le modulation, a radio frequencyampliler, rather than 'a `regenerative cirouit tuned to the 'interinediate'v` frequency may` be 'fusedfor 'further amplification. 2

A- b'etter `nnderstanding o'fjy the prsentmven tibnlmaybeliad b'y Areferring tothefaccompa yflustration o flthe invention and-ismnotto'bgeonl sidered' in anyhwaylimitative- `thereoi. 'In the s Figure Shortwave length radiated electromagnetic-enf.

heingvused befor'the regenerative detection ofthe 'amplfidenergm and .Y A

igur'e 2r illustratesy aj system` siinilar'to'` that shown in Figure. 1Wherein"c'ollected energy ris'a'n'ilpliiiedinapushpull type of,` amplifier before de- 1 no dnation.` s. i t Referring toFieure' 1, ultra short wavelength *,energy is collected npon an 1 antenna I`,v andfi'ed through a," transmission line? tov a tuning circuit "41 vv'The energyv so collected is' resonate tuningvk circuit and" applied4 to the oscilla signal 'l energy'v 'to "produce"k an".intermediateZirequen'cy andjto yvh'ich j is" coupled ta regeneratively connected" detector circuit Y which deniqdulates 'theiamplirled energy. A^su1tablejaudio` irequ'encyLj ampuner' 19; coupled4v to trie' intermediate frel- -e quen'cy regenerative circuit 8,1 supplies energy"A to a-trans'llating device 'such v`as:l phones IOWherein the transmittedsignal i is reproduced y i It "o should vlo'e'noteril that circuit" 8fr isnot4 adjustedfor oscilla- -tions; but only? for regenerative' purposes;

f1-hel mining :circuitry is'compo'si ofisbst fijtially linear-ilconductoref f I'Zg' 14?" connected together: by nieiauici`lr ueshapedf slides-@for trombone slides I6, I8 which provide for variation in tuning of the tuning circuit 4. 'I'he use of U-shaped conductors for varying the tuning of the tuning circuit is advantageous in that the4 length of the tuning circuit and hence the tuning of it can be varied without having any inductive or bothersome tail ends in the circuit.

The linear conductors are closely spacedin order to prevent undesired pick-up,` andare terminated by radioA frequency 'short' circuit/ing means in the form of condensers 6, 3 which prevent the application of high positive control electrode potentials to the anode `of tube A5, the high positive gridpotential being derived from.

a suitable potentiometer 20. By varying the po.- sition of condenser 3 along conductors I2, I4, or by adjusting the junction points of i transmission line 2 along the conductors I 2, I4,'the junction point of the transmission line 2, relative to the standing Wave on the tuning system', can be varied and, consequently, the impedance of the line 2 can be accurately matched,al1owing yof maximum' energy flow into the tuning circuit. e

Oscillator-detector-amplifler tube 5 is also mounted so that it can be variably adjusted through a coil 1 to a potentiometer 22 which supplies through the coil 1, a` suitable potential to the anode of tube 5, ranging from allow positive potential .to negative potentials. Coil 1 couples `the output electrode or plate of tube 5 to there- ,generative circuit 8 which is made to have constants 4corresponding to an appreciablylonger wave length, and, in the case of, at the transmission end, the transmission of double modulated energy, should be tuned to correspond to` they intermediate frequency used at the transmitter.

, The modulation component of the received energywill appear in transformer 24, by-passed by a suitable radio frequency condenser 26. This component may then be amplifiedin a suitable low frequency amplifier 9 and translated by a rsuitable translating device I0..

The regenerativev detector, as illustrated, comprises an electron discharge device 28 having a variable feed back coil 3D coupled to theinput coil-32 and to theoutput coill 1.` Proper biasing potential for'the control electrode of tube.28 is maintained by action of the condenser and'revsistagnce'arrangement 34. j

Experimentation, with the rvarrangement described, has shown it to .amplify equally well l.double modulated ywaves such as alluded to, or ultra short ,waves modulated directly by low frequency signalling currents. Attentionis directed to thefact that in the reception of ultra short Mwave length energy directlyv modulated by low frequency energy, operation ofthe system may vbe attributed to the-fact that therey is interaction ,betweenthe high frequency tuning circuit 4 and regenerative circuit 8, of thelowerfrequency, .theenergy suppliedby tube 5 being modulated by energy of a `frequency corresponding tothe tuning of circuit 8 aswell as` being regeneratively claimis:

l. In apparatus for undulating electrical enamplified in circuit 8. During operation, circuit 8 is preferably not adjusted for the generation of oscillations, buty solely for regenerative amplication.

A modified receivingsystem for ultra short wave length energy, is illustrated schematically in Figure2. `Ultra short wave length energy, collected uponan antenna 40, fed to transmission' lines 42` through .the inductive action of loops 44', 46 is supplied to a resonating circuit 48. Resonating or tuning circuit 48 contains U- 'shaped metallic slides 50, 52. The conductors 62,

'64 of tuningycircuit 48 are connected through `Ltrombone slides 50, 52 to the anodes of tubes 58,

60, whose controlelectrodes are maintained at a relatively high positive potential relative to the other electrodes of the devices by voltage potentiometer 66. The control velectrodes are connected together by conductors 68, 10 having trombone slides 54, 56 therein for varying the effective length of the conductors and hencethe tuning of the control electrode circuit 12. n The positive po'- tential to the grids, of course, is supplied to thel circuit 12 at a voltage nodal point thereof vas indicated.' M 4 e It should be clear that it may be said that adjustment of .all of thetrombone slides Will cause an effective variation in the position of pushpull connected electron discharge devices 58, 68 along conductors 62, 64, and68, 18,

VWith the connections as described,` and with the anodes maintainedat a. negative potential by the action of voltage potentiometer,14the anode circuit will be the most sensitive part of the apparatus, as a consequence of whichthe incoming energy is applied Lthreto. Consequently, variations in the received current will cause Variations in anode current throughthe primary of ytransformer 16 whose secondary may be coupled to a suitable receiver 18 actuating atranslating device80. f .f Y y .Y

vReceiver 18 may be ofthe regenerative type vsuch as described in connection with Figure 4l, or, it may simply be an audio frequency amplifier in which case transformer'` 16 should beso designed as to derive fromthe anode-potential 'supply lead,` the audio frequency component which Will necessarily result'from the application "of the received potentials tothe described circuits. lThe tubes 58, 68, in this case, therefore,

will not only have an amplifying action,` but will also give a demodulating ordetecting action of the received energy. Moreover, in the case `of double modulation at the transmitter,A receiver 18 may comprise a tuned radio frequency amplifier,

`tuned tothe intermediate. frequency as therewill be an intermediate Vfrequency component appearing in the primary of vtransformer 16. 'Ihe amplier should then be followed by a suitable demodulator or detector.

Although I have described in detail some modincations of my invention, it, of course, is not to be limited thereto as it may be altered in several respectsl readilyapparent to those vskilled in the art; and, therefore, my invention is tobe 'pended claims.

Having thus .described invention, e what I ergy, the combination-of aneantenna, au pair of electron discharge devices arranged in push-pull relationship and having'theircathodes connected together and their control electrodes main'- taincd at a positive potential relative tothe anodes and cathodes of said devices for amplifying energy collected upon said antenna, and a regenerative detector coupled to said electron discharge devices for further amplifying and detecting energy amplified by sai-d electron discharge devices.

2. In apparatus for undulating electrical en ergy, the combination of an antenna, electron discharge devices arranged in push-pull fashion` and having their cathodes connected together and their control electrodes at a positive unidirectional potential relative to the anodes and cathodes of said devices for amplifying energy collected upon said antenna, and a regenerative detector coupled to the anode circuit of said electron discharge devices for amplifying and detecting energy amplified by said electron discharge devices.

3. In apparatus for undulatory electrical energy, the combination of an antenna collecting energy of ultra short Wave lengths, a tuning cir-- cuit coupled to said antenna, said tuning circuit comprising closely spaced conductors'short cir-- cuited at their ends for currents of ultra short Wave lengths, means for alteringthe tuning of said ktuning circuit, electron discharge devices having their control electrodes maintained at a positive potential relative to the other electrodes of the devices, coupled to said tuning circuit, a regenerative detector coupled to said devices, and, translating means coupled to said regenerative detector. f

4. In apparatus for undulatory electrical currents, the combination of anantenna collecting ultra short Wave length energy, a tuning circuit coupled to said antenna, U-shaped metallic slides in said tuning circuit for altering the tuning thereof, a push `pull electron dischargel device amplifier operating on the Lsocalled Barkhausen- Kurz principle having its anodes coupled to said `tuning circuit, 4a demodulator coupled to 'said amplier, and translating means coupled to said demodulator. 1

5. In apparatus for undulatory electrical energy, the combination'of an antenna collecting ultra short Wave length energy,`a tuning circuit comprising a pair of kclosely spaced, substantially linear conductors, coupled to said antenna, means for short circuiting said conductors for ultra short Wave length energy, means for varying theeiective lengths of said conductors and consequently the tuning of said tuning circuit, a pair of push pull connected electron vdischarge devices operating on the Barkhausen-Kurz principle having anode electrodes Which are directly coupled to said conductors, a detector alsocoupled to the anodes of said push pull connected devices, and translating means coupled to said detector.v

6; An ultra short Wave receiving circuit comprising a `pair of electron discharge .devices in push-pull relationship, said devices having anode, cathode and control electrodes, means for applying positive -direct current bias potentials to said control electrodes` and smaller potentials to` said anodes relative to the cathodes of said l NILS LINDENBLAD. 

